# Earthquake-case and measurement

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What are the three types of earthquakes?
destructive , constructive , conservative
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What is a destructive margin?
Tension builds up when one plate gets stuck as its moving down past the other into the mantle
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What is a constructive margin?
Tension builds along cracks within the plate as they move away from eachother
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What is a conservative margin?
tension builds up when plates that are grinding past each other get stuck
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The plates eventually jerk past each other , sending out?
shock waves (vibrations)
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The shock waves spread out from the ___.
focus
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What is the focus?
the point in the Earth where the earthquake starts
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What happens near the focus?
the waves are stronger and cause more damage
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Where is the epicentre?
The point on the Earths surface straight above focus
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Weak earthquakes happen often but strong ones are ___
rare
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What two scales are earthquakes measured by?
Richter and Mercalli
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What does the Richter scale measure?
the amount of energy released by an earthquake called magnitude
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The magnitude is measured using a ?
seismometer - a machine with an arm that moves with the vibrations of the Earth
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The Richter scale doesn't have an upper limit and its _________?
logarithmic- this means that an earthquake with a magnitude of 5 is 10 times more powerful than one with a magnitude of 4
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Most people dont't feel earthquakes pf magnitude _____. Major earthquakes are ___
1-2 and 5
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What does the mercalli scale measure ?
This measures the effects of an earthquake
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Effects are measured by?
asking eye witnesses for observations of what happened by a form of words and photos
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Whats the scale?
1-12
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## Other cards in this set

### Card 2

#### Front

What is a destructive margin?

#### Back

Tension builds up when one plate gets stuck as its moving down past the other into the mantle

### Card 3

#### Front

What is a constructive margin?

### Card 4

#### Front

What is a conservative margin?

### Card 5

#### Front

The plates eventually jerk past each other , sending out?